Material Science and Ecological Impact Using 3D Printing Materials

I haven’t exactly been subtle about how sweet 3D print can be…

• https://www.kabt.org/2015/04/06/electrophoresis-is-hard/
• https://www.kabt.org/2015/07/20/diy-circulation-chamber/
• https://www.kabt.org/2019/03/11/3d-printing-authentic-fossil-samples/

The various options I’ve seen and imagined have usually focused on the engineering aspects of making. In biology classrooms, I can do a better job of building maker experiences with rich biological connections. Some community conversations have led me to sharing this idea for a project that marries 3D printing and biology is an interesting way.

h/t Drew, Jessica, and Shannon. Also, Topeka Public Schools STEM teachers for a great conversation while I was considering this article – your work impacted this post.

Context

This project could hit lots of standards, but these are the few I had in mind when I wrote this:

Our driving question is important, and is going to mean different things to different people:

“What plastic should we use when 3D printing?”

I would ask the students to begin operationalizing what that question means to them. There are probably going to be two themes in the answers:

1. What printing materials create the best print products – probably defined by strength.
2. What printing materials have the fewest negative impacts – probably defined by plastic waste consequences.

I will proceed assuming the first question is the initial focus. If that’s the case, I wouldn’t force any consideration of the second question… it will give us a fun payoff later.

Phase 1: Best Print Products

Students can be given time to create a procedure for stress testing parts printed with different plastics.

• Thingiverse is one of many online repositories for 3D parts to be printed
• MatterHackers article “Filament Strength Testing”
• All That 3D article “PLA vs ABS Filament: Plastic Strength, Flexibility Compared! Which Is Better For 3D Printing?”

What’s important throughout this whole testing process is that you ensure students save every print they make. Broken parts, failed prints, unused replicates… everything they print, they keep!

Phase 2: Matter Cycling

After students complete their analysis of strength, they can return to their driving question. Do they have an answer? If they say ‘strongest is best’, then we can let the conversation move on… to clean-up. What do we do with all this PLA and ABS plastic?

If a particular plastic is best, then we can ask them to think about scale. What happens when everyone starts using it? A big draw for PLA is that it’s not petroleum-based (which is good). The issue still remains of disposal. PLA is compostable, and ABS is recyclable… right?

Students can then read this article from engineering.com – “What They Don’t Tell You About 3D Printing PLA”. Despite the title, it lays out a good description of what PLA production and disposal looks like. What does it mean for PLA to only be compostable in “industrial settings”? This article from 3D Printing Industry “Is Recycling PLA Really Better Than Composting” describes the various disposal methods of PLA.

This leads into an opportunity for students to learn about matter cycling and home composting. Ideally, they’d create their own compost piles. They can measure moisture and temperature… lots of great science in a compost project.

Phase 3: Solve a Problem

Now that students have some experience with composting and 3D printing plastic, it’s time for them to solve a problem they themselves have made (all their leftover prints)! The students can design their own methods for adding their PLA printed parts to their compost piles. Here are some resources to help:

• Some Irish researchers showed that a particular plastic combination may biodegrade in home compost settings
  • Students could attempt to work with both kinds of plastic from the research
    • Purchase PLA
    • Purchase PCL
  • These two plastics could be melted together in different blends with high school laboratory equipment.

• Students can compare the impact of the PLA/PCL blending methods on their originally considered model properties with this peer-reviewed paper

Students could implement a method for adding their plastic to the compost piles, and then collect data for the next month or so. Class could shift focus to other topics while students continue monitoring their projects. The extended time frame could provide the students an opportunity to present the results of a major project around the end of a semester.

These are just some rough ideas I had when I came across the first article. There are basically three steps, and you could approach each in lots of different ways:

1. Print.
2. Compost.
3. Design.

What do you think? Anyone want to try it? I’d love to help/consult with someone who wants to give it a shot.